Ward brooks chapman



1,302,963. Patented May 6,1919. 3

C. PARSONS; S. S COOK AND E. CHAPMAN.

' GEAR TRAIN. APPITICATION mzo' 061,30. 19:.

3 SHEETS-SHEET I.

, Inuntonk Chanle a A. Pdrd'ona, JLtapnZe y J. U oab,

GEAR TRAIN.

APPIICATION FILED OCT. 30, 19!?- Patented M (s, 1919 a SHEETS-SHEET 2PAnso n, S'rANLE vwarm Baooxs CIlAPMAN, subjects of the of Great Britainand Ireland, resid- CHARLES ALiI ERNON PABBGNSQ STANLEY SMITHCQOK; ANDEDWARD BROOKS CHAPHL AR, F NEWCASTLEUI'ON-TYNE; ENGLAND; SAID GOOlK ANDSAID ASSIGNOBS 'ros'ana reasons.

;v a GEAR-TRAIN Patented Ma 6, 1919.

Application filed bctobcr 30, 1917. Ierlal No. 198,341.

To all whom it'mag j concern:

Be it known th t we, CHARLES Amennon l SMITH 0001;, and Ening at -HeatonWorks, Newcastle-upon- Tyne. in the'cou'nty of Northumbe'rland,"England, have invented certain new and useful Improvements inGear-Trains, of which the following is a specification.

The present invention rela-testo improvements 1n gear trains and has forits object to construct an intermediate shaft in a gear train in such amanner that itwlll retain a satisfactory alinement under all loadconditions.

t I gear trains having an intermediate carrying a gear wheel and pinionthe principal forces acting on the intermediate shaft of the gear trainwill in general be the tooth reactions of the gear wheels" on the shaftand the weight of the whole shaft.

'These forces, are sustained by the, pressures on the bearings Aft someloads, in cases in which the forces arising from the tooth reactions 1act in an Eupward direction these forces together maybe suflicient toovercome the weight of the shaft and the shaft will risein its bearings.The end toward which a i the pinion lies will rise first, since this isthe lighter end of the shaft. This end is at the same time subject togreater forces from the tooth reactions. There will, therefore, be arange: of loads at which theshaft will tend to lie obliquely between itsbearings, and

with the clearances which it is necessary to provide in practice forhigh speed journals the shaft will lie. obliquely for these intermediateloads, thuspthrowing the teeth of the wheels out of alinement with theteeth with which the have to engage, thus producing unsatis distributionof pressures and high localjgstresseson the teeth.

The resent invention consists in employing a alance weiitonthczintermediate shaft so arranged-"t at the center of gravity of theshafttaken as. a. whole substantially coincides with the point at whichthe resultaiit ofthe other vertical forces acting on shaft crocsestheshaft axis.

The invention-further consists in the improved gear trains hereinafterdcscribedl Referring to the accompanying?draw- 1ngs:--

Figure -1 is an elevation, and

PATENT OFFI Flg. '2 is a plan of a single power unit r in. a I

injhe form of theinvention-illustrated in Figs. 1 and 2, the power unita is prov ded with a double helical pinion bdriving am of the forces forthe double helical gear wheel 0 on the in-.

termediate shaft 03. The intermediate shaft also carries a doublehelical pinion c which drives the gear wheel f on the driven shaft g. -Abalance weight It is placed atthe cud of the intermediate shaft (Zremote from the Fig. 3 shows projected on to a transvcise plane thevertical turning forces, T and T of the intermediate shaft, actingrespectively at the {)t'llllflI'Y and secondary gear teeth. Except forthe small torque necesto overcome friction these forces are inequilibrium about the axis of the shaft. They have therefore a singleresultant G, whose line of action passes through this axis portionalftothe forces T and T and which is equal to the sum of T and T ih Flg. 4 isa vertical section through the axis of theshaft, showing the lineofaction of. the resultant G, and the projections of the lines of actionof the forces T and, T,. The distances m and 7 will be inversely pro-These forces T and T havinglthc resultantG andactingverticallyupwardopefi ate to overcome the weight ofthc,intermediate shaft d and tend. to lift it in its bearinga. Thebalance weight It is attached to slia the resultant G.' The weight W ofthe shaft d and the force G will thus be directly opposed'to eachotherso that with the increasing load when pasing throu h the stage atwhich G .is equal to W the orces will not produce a couple tending totilt the shaft (3. This shaft will therefore rise evenly-in itsbearings. Similarly withdecreasing loads when passin thro shaft will faleven y in its bearings,'and thus, under all conditions .of load, willretain its correct alinement in the vertical plane.

placed diametrically opposite'to each other and transmit equa wheel 0.In this case we have acting on the the axis of the shaft; theyhave,-therefore, a single resultant whose line of action passes throughthe axis. The forces ,T,and t, pro duce no resultant force but only aturning i.

moment which is equal and opposite to the moment of T about the axis ofthe shaft.

The resultant of all these forces is therefore a force acting verticallupward throu h the equal to and in the same transverse plane as T .Inthis case,v

axis of the shaft, an

therefore, the balance weight must be so devsi ed that the center ofgravity ofthe .wole shaft and the line of action of the force T lie inthe same transverse plane.

It will be seen that thebalance Weight may either be integral with theshaft d or may be made separately and attached thereto.

By the above described arrangement we ugh the 'same stage. the,

forces to theprimary described. a

obtain an intermediate shaft which a satisfactory alinement under anyload cond1t1ons.' 3

The invention is particularly advantageous in cases in which it isundesirable to employ separate shafts carrying respectively the hetermediate wheel and pinion with a flexible cou ling connecting them.

aving now described our invention, what we claim as new and desire tosecure by Letters Patent is 1.. In combination in multiple reductiongearing a gear, and a pinion, a shaft on which the pinion is mounted,and a balance weight arranged on the shaft of the pinion ;,in suchpositionthatthe center of gravity of The. diagram Fig. 5 shows theforces inthe case in which two primarypinions b b arei the shaft takenas a wholesubstantially coincide with the point at-which the resultantof theother vertical forces acting on the shaft crosses thev shaft axis,substantially as 2. In combination. .in multiple reduction gearing,a'gear and a pinion meshin with each other, a shaft on which the pinionis mounted, and incansfor pressing said shaft in opposition toitstendency to tilt when, under varying loads, the forces acting in theupward vertical direction become equal to the weight of the shaft, saidmeans consist- .in of a circular weight arranged coaxially w th theshaft and exerting a uniform presthereof, substantially as described.

a 3. In multiplereduction gearing, a driving shaft, a driven shaft, anintermediate shaft a pinion on said drivin shaft, 9. gear said drivenshaft, and a balance weight on said intermediate shaft so arran ed thatthe centerof gravity of the shaft coincides with vsure on said shaft inall angular positions ,wheel en's-aid intermediate s aft, a pinion onsaid intermediate shaft, 9. gear wheel on the point at which theresultant of the other I cellars ALGERNON masons.

STANLEY smm 000x. EDWARD moors CHAPMAN.

